diff options
| author | Andy Lutomirski <luto@amacapital.net> | 2014-10-29 22:33:45 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2014-11-03 21:44:57 +0100 |
| commit | 87983c66bc02c9cd8e4a42e7924435145d52bb13 (patch) | |
| tree | 55948cf6d9d58e55cad84fdfb276819fba65bf6b | |
| parent | x86,vdso: Use LSL unconditionally for vgetcpu (diff) | |
| download | linux-87983c66bc02c9cd8e4a42e7924435145d52bb13.tar.xz linux-87983c66bc02c9cd8e4a42e7924435145d52bb13.zip | |
x86_64, vsyscall: Turn vsyscalls all the way off when vsyscall==none
I see no point in having an unusable read-only page sitting at
0xffffffffff600000 when vsyscall=none. Instead, skip mapping it and
remove it from /proc/PID/maps.
I kept the ratelimited warning when programs try to use a vsyscall
in this mode, since it may help admins avoid confusion.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Link: http://lkml.kernel.org/r/0dddbadc1d4e3bfbaf887938ff42afc97a7cc1f2.1414618407.git.luto@amacapital.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| -rw-r--r-- | arch/x86/kernel/vsyscall_64.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c index 419e83b58436..2d912629c96e 100644 --- a/arch/x86/kernel/vsyscall_64.c +++ b/arch/x86/kernel/vsyscall_64.c @@ -307,6 +307,8 @@ struct vm_area_struct *get_gate_vma(struct mm_struct *mm) if (!mm || mm->context.ia32_compat) return NULL; #endif + if (vsyscall_mode == NONE) + return NULL; return &gate_vma; } @@ -327,7 +329,7 @@ int in_gate_area(struct mm_struct *mm, unsigned long addr) */ int in_gate_area_no_mm(unsigned long addr) { - return (addr & PAGE_MASK) == VSYSCALL_ADDR; + return vsyscall_mode != NONE && (addr & PAGE_MASK) == VSYSCALL_ADDR; } void __init map_vsyscall(void) @@ -335,10 +337,12 @@ void __init map_vsyscall(void) extern char __vsyscall_page; unsigned long physaddr_vsyscall = __pa_symbol(&__vsyscall_page); - __set_fixmap(VSYSCALL_PAGE, physaddr_vsyscall, - vsyscall_mode == NATIVE - ? PAGE_KERNEL_VSYSCALL - : PAGE_KERNEL_VVAR); + if (vsyscall_mode != NONE) + __set_fixmap(VSYSCALL_PAGE, physaddr_vsyscall, + vsyscall_mode == NATIVE + ? PAGE_KERNEL_VSYSCALL + : PAGE_KERNEL_VVAR); + BUILD_BUG_ON((unsigned long)__fix_to_virt(VSYSCALL_PAGE) != (unsigned long)VSYSCALL_ADDR); } |